Question

Is concrete flooring eco-friendly? What's the best way to finish it—stain, paint, polish?

Asked by Nancy Hengerer, Hemet, CA

I want to rip out my old carpet and flooring. Is it eco-friendly to use the remaining concrete slab for flooring? What would be the best way to finish it: stain, paint, or polish?

Answer

Brad Hubbell

Answered by Brad Hubbell

Mill Valley, CA

Hubbell Daily Architecture + Design

June 5, 2007

Concrete can make a terrific and versatile floor.

  • It can be finished with stain or paint, or polished to a glossy sheen.
  • Properly done, all the finishing choices can be durable and environmentally friendly.

Before you rip out your flooring to expose the existing concrete, however, make sure that there is insulation and a vapor barrier below the slab, or that radiant heat is incorporated into its construction.

Preparing an uninsulated concrete floor

If you have neither insulation nor radiant heat, the existing concrete stripped of wood or carpet can become uncomfortably cold.

  • You can deal with this problem by installing an electric radiant heat system on top of the existing concrete and covering it with a relatively thin topping slab of self-leveling concrete.
  • The beauty here is that you are not only improving the heating and comfort of your home, you are also creating an opportunity to add integral stains into the finish slab.

Polishing or cleaning the floor

If your slab is insulated, you can move straight to polishing or cleaning.

If you do not polish the floor, the first thing you will need to do is clean it thoroughly to achieve a high-quality finish. This is especially important if you are using a transparent stain.

  • Some of the standard cleaners—like the strippers used to remove mastic—can be very toxic.
  • Kemiko has a list of less toxic alternatives for cleaning concrete.
  • Also keep in mind that the type of cleaner you use must be compatible with your choice of finish (for example, not all cleaners are compatible with water-based sealers).

If you choose to paint, stain, or dye the concrete, look for water-based products with low VOC emissions.

Sealing the concrete floor

The final step is applying a sealer. There are two categories of sealers:

  • penetrating and
  • film forming.

If you opt for a penetrating sealer, a silicate sealer is best. These sealers are inert and have virtually no VOCs. AFM Safecoat sells sodium silicate products, including Penetrating WaterStop and WaterShield.

For a film-forming sealer, stick with water-based options. Solvent-based sealers have very high VOC levels and contain some of the more hazardous VOCs, such as xylene. Look on the MSDS (material safety data sheet) for the hazardous ingredients and the VOC level.

You can learn more about concrete sealer options on the Concrete Network website.

 

For more information:

Check out GreenHomeGuide's Flooring Know-How articles for more information on concrete flooring.

Central Concrete is a concrete supplier in the San Francisco Bay Area that offers colored concrete for new projects.

Concrete Network is a great resource for the do-it-yourselfer.

Tagged In: radiant heat, concrete floors

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